Packaging for optical transceiver module

ABSTRACT

A packaging method of the optical transceiver module for transmitting optical signals is disclosed. The invention includes a base, a case, a transmission unit and a receiving unit. The transmission unit and the receiving unit contain a circuit board, respectively. The base provides two fixing positions for the installation of the two circuit boards. The two circuit boards are installed horizontally and vertically, respectively. This design increases the utilization of the inner space, providing ideal shielding for the elements and circuit boards. A central beam is used to fix the structure and case in a drawable way like a matchbox. This reduces covered area of the circuit board, making the elements easy to be tested and assembled.

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] The invention relates to an optical transceiver packaging forreceiving and transmitting optical signal. More particularly, theinvention pertains to an optical transceiver packaging convenient formanufacturing and assembly.

[0003] 2. Related Art

[0004] The optical transceiver module is installed in an electronicdevice to emit or receive optical signals through optic fibers.Basically, the optical transceiver module has a case 11, a base 12, areceiver optical subassembly (ROSA) 13, a transmitter opticalsubassembly (TOSA) 14, and a circuit board 15. With reference to FIG. 1,the base 12 supports the circuit board 15, and the case 11 covers thebase 12. The circuit board 15 has the functions oftransmitting/receiving electrical signal to/from TOSA/ROSA. The circuitboard 15 is connected to the electronic device through its pins 151 sothat the electronic device can transmit and receive optical signals viaits transceiving terminal.

[0005] The circuit board 15 is parallel to the base 12, with the emitter14 and the receiver 13 installed on its front end for connecting withoptic fibers. Since the circuit board 15 has both functions oftransmission and reception, it is likely to have crosstalks,deteriorating the signal quality. Any error occurred to the circuitcannot be easily attributed to the reception or transmission.Furthermore, the elements on the circuit board 15 are limited by thesize of the circuit board 15 to be placed fairly close to one another,resulting in serious crosstalk.

[0006] To solve the problem of crosstalks, the prior art has thefunctions of transmission and reception separately on two independentcircuit boards. As shown in FIG. 2, the two circuit boards 16, 17 havethe functions of transmitting and receiving optical signals and connectto the transmitter 14 and the receiver 13, respectively. This can reducethe problem of crosstalks. Moreover, once any error occurs to thesystem, one can easily identify where the problem is. However, since thetwo circuits 16, 17 are installed in parallel, an extra shielding designis needed to completely solve the crosstalk problem. As the wholeoptical transceiver module is small and the two circuit boards 16, 17are shielded from each other, the circuit board assembly and its elementtesting and debugging are limited by the span of the two circuit boards.

SUMMARY OF THE INVENTION

[0007] The invention provides a packaging method for the opticaltransceiver module. It can solve the problems of EMI and crosstalks. Theinvention also efficiently utilizes the inner space of the module toachieve the goals of easy assembly, tests and manufacturing.

[0008] The disclosed packaging method for the optical transceiver moduleincludes a base, a transmission unit, a receiving unit, and a case. Thereceiving unit and the transmission unit contain a circuit board,respectively. The base has two fixing positions for the installation ofthe two circuit boards. The two circuit boards are installedperpendicularly, with one parallel to the base while the otherperpendicular. This design greatly reduces the problems of crosstalksand EMI. On the other hand, the base uses the design of a central beam,so that most of the circuit boards is exposed for convenient assemblyand debugging. The base and the case are combined in a drawable way justlike a matchbox. Therefore, invention can be easily assembled anddifficult to be taken apart.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention will become more fully understood from the detaileddescription given hereinbelow illustration only, and thus are notlimitative of the present invention, and wherein:

[0010]FIG. 1 is a schematic view of a packaging of an opticaltransceiver module in the prior art;

[0011]FIG. 2 is a schematic view of another packaging of an opticaltransceiver module in the prior art;

[0012]FIG. 3 is an explosive view of the invention;

[0013]FIG. 4 is a schematic view of the central beam according to theinvention;

[0014]FIGS. 5A and 5B are two assembly views of the case; and

[0015]FIG. 6 compares the eye diagrams of the invention and the priorart.

DETAILED DESCRIPTION OF THE INVENTION

[0016] According to the optical transceiver packaging method disclosedherein, it includes a base 21, a transmission unit 22, a receiving unit23, and a case 24 (see FIG. 3). The transmission unit 22 contains atransmission circuit board 221 and a laser module 222 connected to itsfront end. The transmission circuit board 221 has pins 223 and severalelectronic elements 224 so that the transmission unit 22 is able to sendout optical signals. Analogously, the receiving unit 23 contains areceiving circuit board 231 and a receptacle 232 and a detector 233 bothconnected to its front end. The receiving circuit board 231 also haspins 234 and several electronic elements 235 so that the receiving unit23 is able to receive optical signals.

[0017] The base 21 provides two fixing positions 211, 212 for thetransmission unit 22 and the receiving unit 23, respectively. One ofthem is installed horizontally and the other vertically (FIG. 5A). Inother words, the transmission circuit board 221 and the receivingcircuit board 231 are perpendicular to each other. This reduces thecrosstalks produced between the transmission unit 22 and the receivingunit 23 to its minimum. Owing to such a horizontal-verticalconfiguration, the internal space can be utilized with more flexibilityand efficiently. Although not shown in the drawing, electric propertiesof the circuit or the metal shielding design thus become flexible.Moreover, the base 21 uses the design of a central beam. That is, asolid beam is provided only at the two fixing positions 211, 212. Such adesign exposes most areas on the transmission circuit board 221 and thereceiving circuit board 231 of the transmission unit 22 and thereceiving unit 23, respectively. The connecting points or electronicelements thereon are thus not shielded. As shown in FIG. 4, thereceiving circuit board 231 is vertical with no shielding on its leftand right sides, while the transmission circuit board 221 is horizontalwith no shielding above or beneath it. This is particularly convenientin assembly and testing in the manufacturing process.

[0018] The central beam design in the base 21 does not cover thesoldering points and the elements at those points on the transmissioncircuit board 221 and the receiving circuit board 231. Therefore, itdoes not require additional text fixture. One only needs to directlyplace the transmission circuit board 221 and the receiving circuit board231 on the fixing positions 211, 212 on the base 21, followed bysoldering and solder the leads of TOSA and ROSA to circuit board. Thefront end of the base 21 is provided with connector sockets 213 forplugging the front ends of the transmission unit 22 and the receivingunit 23, for guiding optic fiber connectors (not shown).

[0019] To meet the electromagnetic compatibility requirements, the case24 can be made of metal. To minimize the number of elements and tofacilitate assembly, the case 24 can be designed like a matchbox. Bothfront and rear ends of the case 24 are open so that the base 21 can beinstalled in and contained inside the case 24. The inner side of itslower surface is formed with one sliding track 241, corresponding to asliding groove 214 at the bottom of the base 21, so that the base 21 canbe easily installed and fixed into the case 24 (see FIGS. 4 and 5A). Theinner surface opposite to the sliding track 241 is a fixing part 242.After the base 21 is completely installed into the case 24, the fixingpart 242 moves into a fixing hole 215 on the base 21 and holds the case24 at this position, as shown in FIG. 5B.

[0020] Please refer to FIG. 6 for the crosstalk effects in the inventionand the prior art. “OES” (the abbreviation for Opto electric and systemsLaboratories in Industrial and Technology Research Institute) in thetable refers to the invention. One can easily see the improvement onreducing the crosstalk.

EFFECTS OF THE INVENTION

[0021] The invention discloses the assembly of an optical transceivermodule. The transmission and receiving parts are designed as twoindependent circuit boards, installed perpendicular to each other on abase. Such a configuration can greatly reduce crosstalks and EMI. Thebase adopts the central beam design to expose most of the area on thecircuit boards. This is particularly convenient for testing, adjustingand assembly. The case and the base are designed to match with eachother so that the assembly is easy.

[0022] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A packaging for an optical transceiver module foran electronic device to receive and transmit optical signals, whichcomprises: a base defining two fixing positions for installation of theelectronic device; a transmission unit emitting optical signals from theelectronic device and contains a transmission circuit board with aplurality of pins, the transmission circuit board being installed at oneof the fixing positions on the base and having electrical communicationswith the electronic device via its pins; and a receiving unit receivingexternal optical signals to the electronic device and contains areceiving circuit board with a plurality of pins, the receiving circuitboard being installed at the other the fixing position on the baseperpendicular to the transmission circuit board and having electricalcommunications with the electronic device via its pins.
 2. The packagingof claim 1 further comprising a case covering the base to reduce EMI(Electromagnetic Interference) between the receiving circuit board andthe transmission circuit board.
 3. The packaging of claim 2, wherein thecase has a sliding track and the base has a sliding groove, the slidingtrack and the sliding groove being designed to match each other so thatthe base is combined with the case by sliding into it.
 4. The packagingof claim 3, wherein the case has a fixing part and the base has acorresponding fixing hole, the combination of which fixes the relativeposition of the case and the base.
 5. The packaging of claim 4, whereinthe fixing part is on the opposite side to that of the sliding track. 6.The packaging of claim 2, wherein the case has a pair of openings forthe pins of the transmission unit and the receiving unit to stick out ofthe case and to form electrical connection with the electronic device.7. The packaging of claim 1, wherein the two fixing positions on thebase are used to install one of the transmission circuit board and thereceiving circuit board perpendicular to the base while the otherparallel to the base.
 8. The packaging of claim 7, wherein the base usesa central beam design so that most of the area on the transmissioncircuit board and the receiving circuit board is exposed to the space.9. The packaging of claim 1, wherein the base contains a metal shieldingunit.